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b9f1cd71db
The doorbells use the content of the PIR register to match messages from other CPUs. This may or may not be the same as our linux CPU number, so using that as the "target" is no right. Instead, we sample the PIR register at boot on every processor and use that value subsequently when sending IPIs. We also use a per-cpu message mask rather than a global array which should limit cache line contention. Note: We could use the CPU number in the device-tree instead of the PIR register, as they are supposed to be equivalent. This might prove useful if doorbells are to be used to kick CPUs out of FW at boot time, thus before we can sample the PIR. This is however not the case now and using the PIR just works. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
43 lines
1.3 KiB
C
43 lines
1.3 KiB
C
/*
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* Copyright 2009 Freescale Semicondutor, Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* provides masks and opcode images for use by code generation, emulation
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* and for instructions that older assemblers might not know about
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*/
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#ifndef _ASM_POWERPC_DBELL_H
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#define _ASM_POWERPC_DBELL_H
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#include <linux/smp.h>
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#include <linux/threads.h>
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#include <asm/ppc-opcode.h>
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#define PPC_DBELL_MSG_BRDCAST (0x04000000)
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#define PPC_DBELL_TYPE(x) (((x) & 0xf) << 28)
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enum ppc_dbell {
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PPC_DBELL = 0, /* doorbell */
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PPC_DBELL_CRIT = 1, /* critical doorbell */
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PPC_G_DBELL = 2, /* guest doorbell */
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PPC_G_DBELL_CRIT = 3, /* guest critical doorbell */
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PPC_G_DBELL_MC = 4, /* guest mcheck doorbell */
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};
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extern void doorbell_message_pass(int target, int msg);
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extern void doorbell_exception(struct pt_regs *regs);
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extern void doorbell_setup_this_cpu(void);
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static inline void ppc_msgsnd(enum ppc_dbell type, u32 flags, u32 tag)
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{
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u32 msg = PPC_DBELL_TYPE(type) | (flags & PPC_DBELL_MSG_BRDCAST) |
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(tag & 0x07ffffff);
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__asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg));
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}
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#endif /* _ASM_POWERPC_DBELL_H */
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